Senate Republicans  boycotted a hearing Thursday to consider President Obama’s nominee for second-in-command at the Department of Homeland Security.

Senate Homeland Security Committee Chairman Tom Carper (D-Del.) declined to postpone the hearing after GOP lawmakers asked for a delay due to concerns about alleged misconduct by Alejandro Mayorkas, whom the president tapped last month to become deputy homeland security secretary.

(J. Scott Applewhite/AP) - .S. Citizenship and Immigration Services Director Alejandro Mayorkas. Alejandro Mayorkas. (J. Scott Applewhite/AP)

An inspector general is investigating whether Mayorkas improperly helped foreign investors obtain U.S. visas through the EB-5 program, which provides green cards to foreign nationals in exchange for investments in projects that create American jobs.

Mayorkas oversees the EB-5 program as director of U.S. Citizenship and Immigration Services. Anthony Rodham,  brother of former secretary of state Hillary Clinton, sought his assistance in obtaining visas on behalf of GreenTech Automotive, according to a Washington Post report Tuesday.

Mayorkas told the committee — minus its eight Republican members — he was unaware of the probe until Monday and that “I have never ever in my career exercised undue influence to influence the outcome of a case.”

“I have never based my decisions on who brings a case but rather on the facts and the law,” Mayorkas added.

For more on Mayorkas’s testimony, see Tom Hamburger’s coverage of the hearing for the Washington Post.

White House counsel Kathryn Ruemmler stood by the president’s pick in a letter to Carper on Wednesday, saying the FBI had conducted a background check of Mayorkas and that the White House had vetted him.

“These standard practices were followed with respect to the nomination of Director Mayorkas, and we have no concerns about his suitability for this important position,” Ruemmler said.

If confirmed by the Senate, Mayorkas is likely to run the Department of Homeland Security until Obama names a replacement for outgoing secretary Janet Napolitano, who has said she will leave the agency in September to head the sprawling University of California system.

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